1. Field of the Invention
The invention relates generally to electrical switch assemblies and in particular to those switch assemblies which are capable of providing the operator with tactile feedback, i.e. touch perceived information that a switch assembly has been actuated from an open state to a closed state or vice versa.
2. Description of the Prior Art
Preferably, an electrical switch assembly should have a minimal number of parts and be small in size, and yet remain rugged, reliable and contaminant resistant. There have been many attempts to develop inexpensive reliable switch assemblies which have these capabilities. For example, in U.S. Pat. No. 4,343,973, granted Aug. 10, 1982, there is disclosed a multiple single-stage switch assembly. The switch assembly is a snap-acting push button type which includes a pair of electrically interconnected, conducting, snap action domes or convex discs disposed in side-by-side relation on a common base. Each of the snap action domes have center portions elevated above peripheral portions. This provides an over center snapping effect when downward pressure is applied to the center portions by respective push buttons. The operator pressing down on a push button can sense the over center snapping movement of the center portion of a dome. This sensation is commonly referred to as tactile feedback. When the operator releases the push button, however, the dome snaps back to its normal position. This snapping inwardly and outwardly of the dome is used to establish and break an electrical connection. Thus, the dome functions as a bi-state switching element.
While the multiple switch assembly disclosed in U.S. Pat. No. 4,343,973 is capable of providing tactile feedback to the operator to indicate switch closing, it has several problems. For example, arranging the pair of domes in side-by-side relation makes the multiple switch assembly unduly large and adds to the number of required parts, thereby increasing the cost to manufacture such switch assembly. Moreover, the side-by-side relation of the two domes necessitates a side-by-side relation of the associated push buttons. This, unfortunately, allows the operator to press the two push buttons in the wrong sequence.
3. The Cross Referenced Application
A commonly assigned application is cross-referenced above for information purposes. That application discloses a single dome, multi-stage switch assembly.